package ch3;

/**
 * Created by 竹韵澜 on 2017/7/16.
 * Math类，pow,aqrt方法
 */

//********************************************************************
// Quadratic.java Java Foundations
//
// Demonstrates the use of the Math class to perform a calculation
// based on user input.
//********************************************************************

import java.util.Scanner;

public class Quadratic {
    //-----------------------------------------------------------------
    // Determines the roots of a quadratic equation.
    //-----------------------------------------------------------------

    public static void main (String[] args) {
        int a, b, c; // ax^2 + bx + c
        double discriminant, root1, root2;

        Scanner scan = new Scanner (System.in);

        System.out.print ("Enter the coefficient of x squared: ");
        a = scan.nextInt();

        System.out.print ("Enter the coefficient of x: ");
        b = scan.nextInt();

        System.out.print ("Enter the constant: ");
        c = scan.nextInt();

        // Use the quadratic formula to compute the roots.
        // Assumes a positive discriminant.
        discriminant = Math.pow(b, 2) - (4 * a * c);
        root1 = ((-1 * b) + Math.sqrt(discriminant)) / (2 * a);
        root2 = ((-1 * b) - Math.sqrt(discriminant)) / (2 * a);

        System.out.println ("Root #1: " + root1);
        System.out.println ("Root #2: " + root2);
    }
}
